I can’t speak for exhibitors. I haven’t done H/Js for eons, though I do still care about them.
Shows with large prize money and/or big trainer prestige on the line (the “trainer of the Champion Open Hunter at Devon, WIHS, WEF” advertising resume ) could be the places start, the places to test.
Champion and Reserve? Governing bodies are there for the express purpose of governing aren’t they? The welfare of the horse is supposed to be important isn’t it?
Honestly, I think USEF and USHJA need to crack down. Prioritize their use of the funds available to them. Stop making excuses and DO something. The injection rule is a start. Rules are fine and there are plenty of them. Unfortunately, enforcement is necessary to keep people from breaking them.
Of course this may not be possible given the status quo.
When the people who are in governance (and thus are making the rules) and/or training are also competing and sometimes being caught violating the rules themselves, the problem may be so entrenched that there is no hope. I do hope that this isn’t the case.
As for being able to spot a drugged horse? I sure can’t unless I am standing right next to it, it’s a horse I’ve known very well (and close up as in grooming) for years and, actually, my first thought would go to illness before drugs.